/*
** $Id: ldblib.c,v 1.132 2012/01/19 20:14:44 roberto Exp $
** Interface from Lua to its debug API
** See Copyright Notice in lua.h
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ldblib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#define HOOKKEY "_HKEY"



static int db_getregistry(lua_State *L) {
    lua_pushvalue(L, LUA_REGISTRYINDEX);
    return 1;
}


static int db_getmetatable(lua_State *L) {
    luaL_checkany(L, 1);
    if (!lua_getmetatable(L, 1)) {
        lua_pushnil(L);  /* no metatable */
    }
    return 1;
}


static int db_setmetatable(lua_State *L) {
    int t = lua_type(L, 2);
    luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                  "nil or table expected");
    lua_settop(L, 2);
    lua_setmetatable(L, 1);
    return 1;  /* return 1st argument */
}


static int db_getuservalue(lua_State *L) {
    if (lua_type(L, 1) != LUA_TUSERDATA)
        lua_pushnil(L);
    else
        lua_getuservalue(L, 1);
    return 1;
}


static int db_setuservalue(lua_State *L) {
    if (lua_type(L, 1) == LUA_TLIGHTUSERDATA)
        luaL_argerror(L, 1, "full userdata expected, got light userdata");
    luaL_checktype(L, 1, LUA_TUSERDATA);
    if (!lua_isnoneornil(L, 2))
        luaL_checktype(L, 2, LUA_TTABLE);
    lua_settop(L, 2);
    lua_setuservalue(L, 1);
    return 1;
}


static void settabss(lua_State *L, const char *i, const char *v) {
    lua_pushstring(L, v);
    lua_setfield(L, -2, i);
}


static void settabsi(lua_State *L, const char *i, int v) {
    lua_pushinteger(L, v);
    lua_setfield(L, -2, i);
}


static void settabsb(lua_State *L, const char *i, int v) {
    lua_pushboolean(L, v);
    lua_setfield(L, -2, i);
}


static lua_State *getthread(lua_State *L, int *arg) {
    if (lua_isthread(L, 1)) {
        *arg = 1;
        return lua_tothread(L, 1);
    } else {
        *arg = 0;
        return L;
    }
}


static void treatstackoption(lua_State *L, lua_State *L1, const char *fname) {
    if (L == L1) {
        lua_pushvalue(L, -2);
        lua_remove(L, -3);
    } else
        lua_xmove(L1, L, 1);
    lua_setfield(L, -2, fname);
}


static int db_getinfo(lua_State *L) {
    lua_Debug ar;
    int arg;
    lua_State *L1 = getthread(L, &arg);
    const char *options = luaL_optstring(L, arg + 2, "flnStu");
    if (lua_isnumber(L, arg + 1)) {
        if (!lua_getstack(L1, (int)lua_tointeger(L, arg + 1), &ar)) {
            lua_pushnil(L);  /* level out of range */
            return 1;
        }
    } else if (lua_isfunction(L, arg + 1)) {
        lua_pushfstring(L, ">%s", options);
        options = lua_tostring(L, -1);
        lua_pushvalue(L, arg + 1);
        lua_xmove(L, L1, 1);
    } else
        return luaL_argerror(L, arg + 1, "function or level expected");
    if (!lua_getinfo(L1, options, &ar))
        return luaL_argerror(L, arg + 2, "invalid option");
    lua_createtable(L, 0, 2);
    if (strchr(options, 'S')) {
        settabss(L, "source", ar.source);
        settabss(L, "short_src", ar.short_src);
        settabsi(L, "linedefined", ar.linedefined);
        settabsi(L, "lastlinedefined", ar.lastlinedefined);
        settabss(L, "what", ar.what);
    }
    if (strchr(options, 'l'))
        settabsi(L, "currentline", ar.currentline);
    if (strchr(options, 'u')) {
        settabsi(L, "nups", ar.nups);
        settabsi(L, "nparams", ar.nparams);
        settabsb(L, "isvararg", ar.isvararg);
    }
    if (strchr(options, 'n')) {
        settabss(L, "name", ar.name);
        settabss(L, "namewhat", ar.namewhat);
    }
    if (strchr(options, 't'))
        settabsb(L, "istailcall", ar.istailcall);
    if (strchr(options, 'L'))
        treatstackoption(L, L1, "activelines");
    if (strchr(options, 'f'))
        treatstackoption(L, L1, "func");
    return 1;  /* return table */
}


static int db_getlocal(lua_State *L) {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    const char *name;
    int nvar = luaL_checkint(L, arg + 2); /* local-variable index */
    if (lua_isfunction(L, arg + 1)) {  /* function argument? */
        lua_pushvalue(L, arg + 1);  /* push function */
        lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */
        return 1;
    } else { /* stack-level argument */
        if (!lua_getstack(L1, luaL_checkint(L, arg + 1), &ar)) /* out of range? */
            return luaL_argerror(L, arg + 1, "level out of range");
        name = lua_getlocal(L1, &ar, nvar);
        if (name) {
            lua_xmove(L1, L, 1);  /* push local value */
            lua_pushstring(L, name);  /* push name */
            lua_pushvalue(L, -2);  /* re-order */
            return 2;
        } else {
            lua_pushnil(L);  /* no name (nor value) */
            return 1;
        }
    }
}


static int db_setlocal(lua_State *L) {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    if (!lua_getstack(L1, luaL_checkint(L, arg + 1), &ar)) /* out of range? */
        return luaL_argerror(L, arg + 1, "level out of range");
    luaL_checkany(L, arg + 3);
    lua_settop(L, arg + 3);
    lua_xmove(L, L1, 1);
    lua_pushstring(L, lua_setlocal(L1, &ar, luaL_checkint(L, arg + 2)));
    return 1;
}


static int auxupvalue(lua_State *L, int get) {
    const char *name;
    int n = luaL_checkint(L, 2);
    luaL_checktype(L, 1, LUA_TFUNCTION);
    name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
    if (name == NULL) return 0;
    lua_pushstring(L, name);
    lua_insert(L, -(get + 1));
    return get + 1;
}


static int db_getupvalue(lua_State *L) {
    return auxupvalue(L, 1);
}


static int db_setupvalue(lua_State *L) {
    luaL_checkany(L, 3);
    return auxupvalue(L, 0);
}


static int checkupval(lua_State *L, int argf, int argnup) {
    lua_Debug ar;
    int nup = luaL_checkint(L, argnup);
    luaL_checktype(L, argf, LUA_TFUNCTION);
    lua_pushvalue(L, argf);
    lua_getinfo(L, ">u", &ar);
    luaL_argcheck(L, 1 <= nup && nup <= ar.nups, argnup, "invalid upvalue index");
    return nup;
}


static int db_upvalueid(lua_State *L) {
    int n = checkupval(L, 1, 2);
    lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
    return 1;
}


static int db_upvaluejoin(lua_State *L) {
    int n1 = checkupval(L, 1, 2);
    int n2 = checkupval(L, 3, 4);
    luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
    luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
    lua_upvaluejoin(L, 1, n1, 3, n2);
    return 0;
}


#define gethooktable(L) luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)


static void hookf(lua_State *L, lua_Debug *ar) {
    static const char *const hooknames[] =
    {"call", "return", "line", "count", "tail call"};
    gethooktable(L);
    lua_pushthread(L);
    lua_rawget(L, -2);
    if (lua_isfunction(L, -1)) {
        lua_pushstring(L, hooknames[(int)ar->event]);
        if (ar->currentline >= 0)
            lua_pushinteger(L, ar->currentline);
        else lua_pushnil(L);
        lua_assert(lua_getinfo(L, "lS", ar));
        lua_call(L, 2, 0);
    }
}


static int makemask(const char *smask, int count) {
    int mask = 0;
    if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
    if (strchr(smask, 'r')) mask |= LUA_MASKRET;
    if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
    if (count > 0) mask |= LUA_MASKCOUNT;
    return mask;
}


static char *unmakemask(int mask, char *smask) {
    int i = 0;
    if (mask & LUA_MASKCALL) smask[i++] = 'c';
    if (mask & LUA_MASKRET) smask[i++] = 'r';
    if (mask & LUA_MASKLINE) smask[i++] = 'l';
    smask[i] = '\0';
    return smask;
}


static int db_sethook(lua_State *L) {
    int arg, mask, count;
    lua_Hook func;
    lua_State *L1 = getthread(L, &arg);
    if (lua_isnoneornil(L, arg + 1)) {
        lua_settop(L, arg + 1);
        func = NULL;
        mask = 0;
        count = 0;  /* turn off hooks */
    } else {
        const char *smask = luaL_checkstring(L, arg + 2);
        luaL_checktype(L, arg + 1, LUA_TFUNCTION);
        count = luaL_optint(L, arg + 3, 0);
        func = hookf;
        mask = makemask(smask, count);
    }
    if (gethooktable(L) == 0) {  /* creating hook table? */
        lua_pushstring(L, "k");
        lua_setfield(L, -2, "__mode");  /** hooktable.__mode = "k" */
        lua_pushvalue(L, -1);
        lua_setmetatable(L, -2);  /* setmetatable(hooktable) = hooktable */
    }
    lua_pushthread(L1);
    lua_xmove(L1, L, 1);
    lua_pushvalue(L, arg + 1);
    lua_rawset(L, -3);  /* set new hook */
    lua_sethook(L1, func, mask, count);  /* set hooks */
    return 0;
}


static int db_gethook(lua_State *L) {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    char buff[5];
    int mask = lua_gethookmask(L1);
    lua_Hook hook = lua_gethook(L1);
    if (hook != NULL && hook != hookf)  /* external hook? */
        lua_pushliteral(L, "external hook");
    else {
        gethooktable(L);
        lua_pushthread(L1);
        lua_xmove(L1, L, 1);
        lua_rawget(L, -2);   /* get hook */
        lua_remove(L, -2);  /* remove hook table */
    }
    lua_pushstring(L, unmakemask(mask, buff));
    lua_pushinteger(L, lua_gethookcount(L1));
    return 3;
}


static int db_debug(lua_State *L) {
    for (;;) {
        char buffer[250];
        luai_writestringerror("%s", "lua_debug> ");
        if (fgets(buffer, sizeof(buffer), stdin) == 0 ||
                strcmp(buffer, "cont\n") == 0)
            return 0;
        if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
                lua_pcall(L, 0, 0, 0))
            luai_writestringerror("%s\n", lua_tostring(L, -1));
        lua_settop(L, 0);  /* remove eventual returns */
    }
}


static int db_traceback(lua_State *L) {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    const char *msg = lua_tostring(L, arg + 1);
    if (msg == NULL && !lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */
        lua_pushvalue(L, arg + 1);  /* return it untouched */
    else {
        int level = luaL_optint(L, arg + 2, (L == L1) ? 1 : 0);
        luaL_traceback(L, L1, msg, level);
    }
    return 1;
}


static const luaL_Reg dblib[] = {
    {"debug", db_debug},
    {"getuservalue", db_getuservalue},
    {"gethook", db_gethook},
    {"getinfo", db_getinfo},
    {"getlocal", db_getlocal},
    {"getregistry", db_getregistry},
    {"getmetatable", db_getmetatable},
    {"getupvalue", db_getupvalue},
    {"upvaluejoin", db_upvaluejoin},
    {"upvalueid", db_upvalueid},
    {"setuservalue", db_setuservalue},
    {"sethook", db_sethook},
    {"setlocal", db_setlocal},
    {"setmetatable", db_setmetatable},
    {"setupvalue", db_setupvalue},
    {"traceback", db_traceback},
    {NULL, NULL}
};


LUAMOD_API int luaopen_debug(lua_State *L) {
    luaL_newlib(L, dblib);
    return 1;
}

